U2F Zero

Overview

U2F Zero is an affordable and physically secure two factor authentication token that implements the U2F protocol.

Firmware

Code overview

The HID layer for U2F is implemented in u2f_hid.c. The USB boilerplate is in callback.c.

Firmware generally works as follows:

• Main loop adds a request for USB to read a 64 byte packet
• USBD_XferCompleteCb gets called with packet when it comes
• U2F HID layer gets called
• U2F HID layer will call U2F layer when appropriate

U2F HID layer spec

U2F layer spec

Using Simplicity Studio

• Open Simplicity Studio
• Click File -> Import
• General -> Existing Projects into Workspace
• Select root directory and choose the firmware/ directory
• Finish

Using command line tools

• TODO